ST. PETERSBURG — Talking about players who can have the widest range of impact on the Rays this season, second-year lefty Blake Snell quickly becomes a leading man in the discussion.And that wasn't based just on Thursday night, when he showed both the ability to be the dominating starter the Rays are certain he has the talent to be and to make the kind of mistakes that leave you wondering if he will ever learn.As a result, as the 5-2 loss to the Blue Jays showed, Snell has much to do about some things.The 6? innings, for example, matched his career high. But so did the five walks, made worse as three ended up scoring.He looked very sharp through the first two innings. Then he made quite the mess in the third, loading the bases on a single and two two-out walks, and making the mistake that defined the game, allowing a grand slam to Kendrys Morales, who is playing the role of Edwin Encarnacion in this year's edition of the Blue Jays power show. RAYS TAKEAWAYS: Three things from the loss to the Blue Jays. Snell rebounded to pitch into the seventh inning. But a leadoff walk, and his mistake of not covering first base on a bunt, cost him another run, and a batter later ended his night at 97 pitches.Manager Kevin Cash's postgame comments were similarly diverse.He praised Snell, 24, for how well he threw overall and for not giving in after the grand slam, but Cash also noted that the troubled walks need to be "corrected" and how Snell got too fine in key situations, needing to put more trust in his stuff.Snell, too, had a mixed review."Walks, that's always been the thing that gets me," he said. "I've just got to attack. I feel like I did really good attacking today. I've just got to do some things mentally to stay into it, finish."But they're things I can fix, things I'm aware of so I can get better at it."Snell is not the only Ray with a wide swath between extremes in which he could end up.Rightfielder Steven Souza Jr. is one, given the potential to be a five-tool impact beast — and off to an impressive start this week — or to play his way into being a platoon guy playing only against lefties, or even back to the minors.Shortstop Tim Beckham is another, with the upside that he takes advantage of his long-awaited opportunity to show he can be everyday big-leaguer, to the downside that he plays his way out of the job before planned starter Matt Duffy makes it back from injury. BOXBERGER UPDATE: Tendon strain in pitching elbow slows Brad Boxberger's return. And so, too, is Mallex Smith, from a small sample size, might be a fourth, given the ability he has shown to disrupt innings and change momentum with his speed balanced by rawness in parts of his game.There are others, too. But Snell is atop the list, and Thursday's game log provided a telling tale.After retiring seven of the first eight Jays, Snell allowed a single with one out in the third inning to No. 9 hitter Darwin Barney, but he then struck out ex-mate Steve Pearce.But Snell fell behind dangerous Josh Donaldson 2-and-0, walking him to put two on.And then he fell behind even more dangerous Jose Bautista and walked him to load the bases.And then he made the biggest mistake of all after a first-pitch foul, leaving a 95 mph fastball over the middle of the plate that Morales crushed over the left-centerfield wall.Is Snell going to be the pitcher the Rays say has the talent to potentially join the parade of talented lefties they have produced led by David Price and Matt Moore? WHAT THEY MAKE: Check out the 2017 Rays salaries Or is he going to show the inconsistency and occasional nonchalance from spring training that left them questioning — at times infuriatingly so — if he will ever maximize that talent."Blake's going to be just fine," Cash said. "We're very confident in that. I'm very confident in that."He's giving us a reason now just because of the stuff and how it's played and the swings and misses he's getting." Marc Topkin can be reached at firstname.lastname@example.org. Follow @ TBTimes_Rays.